NIKAIA (or Nicaea) was the NaiadNymph of the springs or fountain of the Greek colony of Nikaia in Bithynia (north-western Anatolia). She was a devotee of the goddess Artemis, who was seduced by Dionysos with the help of the god of sleep, Hypnos.

She appears to have been closely identified with Aura, a daughter of the Phrygian goddess Kybele (Cybele), who was also raped by Dionysos. Both were probably merely Greek translation of local goddesses.

ENCYCLOPEDIA

NICAEA (Nikaia), a nymph, the daughter of the river-god Sangarius and Cybele. She was beloved by a shepherd, Hymnus, and killed him, but Eros took vengeance upon her. and Dionysus, who first intoxicated her, made her mother of Telete, whereupon she hung herself. Dionysus called the town of Nicaea after her. (Nonnus, Dionys. xvi.; Memnon, ap. Phot. Bibl. p. 233, ed. Bekker.)

Source: Dictionary of Greek and Roman Biography and Mythology.

The story of Nikaia from book 15 Nonnus' Dionysiaca is not currently quoted here. A summary of the story from "Women of Classical Mythology" tells us: Nikaia was loved by the shepherd Hymnos, but a follower of Artemis she was distressed by his persistance and shot him through the heart with an arrow. Eros furious over her cruelty inspired Dionysos to fall in love with her. He pursued her for a long time but she resisted until he contrived to get her drunk and then had his way with her. Their child was Telete who became a follower of Dionysos. The city of Nikaia was named for her.

Nonnus, Dionysiaca 48. 567 ff (trans. Rouse) (Greek epic C5th A.D.) :
"He [Dionysos] remembered the bed of the Astakid Nymphe [Nikaia (Nicaea) of Lake Astakos] long before, how he had wooed the lovely Nymphe with a cunning potion and made sleep his guide to intoxicated bridals."

Nonnus, Dionysiaca 48. 811 ff :
"Nikaia (Nicaea), the leader of the rites of Lyaios, seeing the pain and disgrace of distracted Aura [pregnant after being raped by Dionysos], spoke to her thus in secret pity:
‘Aura, I have suffered as you have [Nikaia was also raped by Dionysos whilst in a drunken sleep], and you too lament you your maidenhood. But since you carry in your womb the burden of painful childbirth, endure after the bed to have the pangs of delivery, endure to give your untaught breast to babes. Why did you also drink wine, which robbed me of my girdle? Why did you also drink wine, Aura, until you were with child? You also suffered what I suffered, you enemy of marriage; then you also have to blame a deceitful sleep sent by the Erotes (Loves), who are friends of marriage. One fraud fitted marriage on us both, one husband was Aura’s and made virgin Nikaia the mother of children. No more have I a beastslaying bow, no longer as once, I draw my bowstring and my arrows; I am a poor woman working at the loom, and no longer a wild Amazon.’
She spoke, pitying Aura's labour to accomplish the birth, as one who herself had felt the pangs of labour."

Nonnus, Dionysiaca 48. 865 ff :
"Dionysos called Nikaia (Nicaea), his own Kybeleid (Cybelid) Nymphe, and smiling pointed to Aura still unbraiding her childbed; proud of his late union with the lonely girl, he said: ‘Now at last, Nikaia, you have found consolation for your love. Now again Dionysos has stolen a marriage bed, and ravished another maiden: woodland Aura in the mountains, who shrank once from the very name of love, has seen a marriage the image of yours. Not you alone had sweet sleep as a guide to love, not you alone drank deceitful wine which stole your maiden girdle; but once more a fountain of nuptial wine has burst from a new opening rock unrecognised, and Aura drank. You who have learnt the throes of childbirth in hard necessity, by Telete your danceweaving daughter I beseech you, hasten to lift up my son, that my desperate Aura may not destroy him with daring hands--for I know she will kill one of the two baby boys in her intolerable frenzy, but do you help Iakkhos: guard the better boy, that your Telete may be the servant of son and father both.’
With this appeal Bakkhos departed, triumphant and proud of his two Phrygian marriages, with the elder wife and the younger bride . . . [Artemis rescued one of the sons of Aura before the mother could kill both of her newborn babes and carried him to Dionysos.]
The father gave charge of his son [Iakkhos, Iacchus] to Nikaia the Nymphe as a nurse. She took him, and fed the boy, pressing out the lifegiving juice of her childnursing breasts from her teat, until he grew up."